Method and system for making extruded portions of cheese

ABSTRACT

A method and system are provided for portioning a cheese mass to be sliced and shredded directly from a quantity of bulk cheese, without the need to thermally process the cheese. The cheese extrudate strands and sheets are cut to provide discrete cheese shreds and slices, and can be automatically portioned and deposited in packages.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent Ser. No.11/533,235, filed on Sep. 19, 2006, which in turn is acontinuation-in-part of U.S. patent application Ser. No. 11/229,662,filed on Sep. 20, 2005. Priority from both applications is claimed, andthe contents of both applications are hereby incorporated by referencein their entireties.

FIELD OF THE INVENTION

The present invention relates generally to a method and system forportioning shredded or sliced cheese.

BACKGROUND OF THE INVENTION

Shredded cheese, or cheese in the form of elongated shreds or othershapes, is commonly used as a food topping, such as a pizza topping,etc. Sliced cheese is commonly used in making sandwiches or for use as asnack, such as in a Lunchables® package. Automated conversion of bulkpieces of cheese, such as blocks or loaves, into shreds or slices aspart of a continuous operation is technologically challenging.Commercially-available equipment for automated shredding or slicing ofcheese in high volumes is scarce.

Cheeses, such as mozzarella, that may be relatively elastic in loaf orbrick form at ambient conditions can be particularly difficult to formdirectly into shreds of substantially uniform dimensions. Milling hasbeen used as one way to convert mozzarella loaf into shreds. However,the elasticity of the mozzarella cheese can make milling type shreddingdifficult to practice. Depending on the process set-up, mozzarellacheese loaves and bricks may be stored under refrigerated conditionsuntil subjected to subsequent shredding operations. The chilled cheesetends to toughen, making it even more difficult to shred into shred-likepieces or strands of substantially uniform size. Mozzarella cheese loafhas been heated to a molten condition in an extruder, and thendischarged under compressive force through circular die holes of a dieplate to form cheese strings, which are cooled in a brine solution. Thecheese extrudates are cooled immediately upon extrusion before theydeform, stick together, and/or otherwise lose the discrete elongatedshape imparted by the extruder die. The conversion of the cheese tomolten form and post-extrusion brine treatment increase processcomplexity and cost.

There also is a demand for low fat mozzarella cheeses in particular,which tend to have higher moisture content than the full fat counterpartproducts. At higher moisture content, some cheeses, such as mozzarellacheese, tend to become softer, making it even more difficult to shredthe cheese using conventional shredding techniques.

In addition, some cheeses may be sliced instead of shredded. The cheeseslices can be produced in bulk ribbon pieces which are then cut intoslices by using wires to cut the ribbon into sheets and subsequentlyinto slices. The cheese slices cut in this manner tends to sticktogether and the slices may be required to be separated from other slicestacks by hand.

Whether sliced or shredded, the bulk cheese can be portioned anddeposited into food packaging. A pick and place method has been used toput the cheese slices or shreds into the food packaging. This method canbe expensive on a large scale. Moreover, the more the sliced or shreddedcheese is handled, the greater the likelihood that the cheese will sticktogether.

There is a need for arrangements for forming cheese loaf, blocks orpieces directly into stable elongated shreds or slices, and particularlychilled high moisture content cheese loaf, in an automated, non-manualmanner without the need to heat process the cheese. As will becomeapparent from the descriptions that follow, the invention addressesthese needs as well as providing other advantages and benefits.

SUMMARY OF THE INVENTION

The invention provides a method and system for forming shredded cheesedirectly from a quantity of cheese in an automated manner without theneed to thermally process the cheese. In general, cheese shreds areformed from a quantity of cheese in which at least one discrete cheesepiece is introduced into an elongated chamber which houses a conveyoroperable to form homogenous cheese mass from the at least one cheesepiece. Resulting cheese mass is transported forwardly and longitudinallyof the chamber via the conveyor to a discharge outlet of the chamber.The cheese mass is pumped to a die plate under positive pressure. Thecheese mass is extruded as continuous cheese extrudate strands at atemperature of less than about 50° F. through a plurality of elongatedorifices of the die plate which receives the cheese mass after dischargefrom the chamber. The cheese extrudate strands are cut intermittentlyalong their lengths to form discrete cheese shreds.

The cheese shred products obtained by the method and system of thepresent invention have cross-sectional shapes substantiallycorresponding to the shapes of the orifices in the die plate. Processingthe cheese mass at temperatures less than about 50° F. improves themicrobiological stability of the product. It also reduces and avoidsheat distortions from occurring in the shred product shape. Itadditionally eliminates the need for rapid quenching of hot cheeseextrudates. This inventive method and system avoids the need for processcontrol over complex systems incorporating heating jackets or internalheating systems in the extruder, piping, pumps, dies, etc. This reducesprocess complexity, requirements and costs. The cheese shreds may bedeposited directly on food products or in food packaging tray cells aspart of a food product manufacturing line. For instance, this automatedmethod and system eliminates the need to use intensive manual labor toplace cheese shreds as toppings upon pizza products or in food packagingtray cells, or difficult to control conventional shred sprinklingsystems like vibratory belts. Alternatively, they may be collected forpackaging as a shredded cheese product per se.

In one particular embodiment, the cheese shreds may be depositeddirectly onto an intermediate food product, such as a dough-containingproducts like pizza, facilitating food production such as by minimizingprocessing losses and weight variability. The types of cheese which maybe processed according to embodiments of this invention include naturalcheeses, process cheeses, and cheese analogs or substitutes, or mixturesthereof. In one embodiment, the cheese is mozzarella or other pastafilata cheese, or other varieties of cheese, such as Emmental (Swiss),Cheddar, Gouda, Edam, etc. In one particular embodiment, cheese shredsare produced from refrigerated, high-moisture content cheese with themethod and system of embodiments herein. In a more particularembodiment, the cheese being processed is high moisture-content pastafilata cheese, such as mozzarella loaves, bricks, etc., having at leastabout 52% moisture-content. The methods in accordance with embodimentsof this invention make it feasible to extrude high-moisture contentcheese at temperatures less than about 50° F. in strand-form.

In one embodiment, the high-moisture cheese may comprise refrigeratedmozzarella cheese having a moisture content of at least about 52%, whichis processed under unheated conditions in the inventive shreddingsystem. In a particular embodiment, the cheese pieces are introducedinto, processed within the extruder, and extruded in strand-form at thedie plate, at a temperature less than about 45° F., more particularly,less than about 40° F. In one aspect, refrigerated cheese is fed intothe extruder chamber, and the cheese mass formed therefrom in theextruder is conveyed to the die plate, while being maintained underrefrigerated temperature conditions. In one aspect, the temperature ofthe cheese when extruded at the die plate is about 32° F. to about 45°F., particularly about 35° F. to about 45° F. In this manner, it ispossible to directly convert refrigerated or otherwise chilled cheesepieces into shreds of approximately uniform dimensions without the needto heat the cheese to flowable or molten state to assist extrusion,which avoids the need to provide post-extrusion quench procedures tostabilize and avoid shape distortion from occurring in otherwise hotextruded shapes.

In another particular embodiment, a pump is used to force cheese througha single or multiple large diameter showerhead type dies with elongatedorifices resembling the desired cross-sectional shape of a cheese shred.This pump includes a screw-type vacuum filler which receives the cheesein blocks of equal or different sizes and compresses the cheese into anairless homogenous flow without damaging the physical or flavorcharacteristics of the cheese. The cheese mass is extruded at atemperature of less than about 50° F. through the elongated die orificesafter it exits the discharge outlet of the chamber, providing cheeseextrudate strands. In one embodiment, a reciprocating multiwire cutterthat translates rotationally relative to the die plate is used to cutthe extrudate strands into shreds of desired length.

In a more particular embodiment, the die plate used in methods inaccordance with embodiments herein includes a plurality of passagewaysextending from the above-indicated plurality of elongated orifices at adischarge side of the die plate to an inlet side thereof for receivingcheese mass discharged from the discharge outlet of the chamber. Forpurposes herein, “elongated” orifice shapes have a major diameterdimension which is at least 25%, preferably at least about 50%, largerin dimension than a minor diameter dimension oriented approximately 90degrees thereto. In one embodiment, the passageways have substantiallyuniform cross-sectional shape corresponding with the elongated shape ofthe orifices. The orifices are non-circular and particularly aregenerally oval shaped or almond shaped. In one embodiment, the orificeshave a major diameter/minor diameter ratio of about 2.25:1 to about1.75:1. The orifices have a major dimension of about 6 mm to about 6.5mm, and a minor dimension of about 3 mm to about 3.25 mm. In oneembodiment, the die plate may have a thickness, which corresponds withthe length of the passageways therein, of approximately 6 mm toapproximately 13 mm. Alternatively, the elongated orifices may be slotsthat are generally rectangular in shape and are located between cuttingelements in order to produce slices.

In another particular embodiment, the cheese mass formed in the extruderis divided into multiple output streams with a water wheel, which feedsthe output streams under pressure to respective die plates, which areoperable for extruding continuous cheese extrudates through elongatedorifices, which are cut into discrete shreds, at a plurality of foodproduction lanes. The shreds may be deposited directly on a food productas a topping or in a food tray cell in each lane.

The extruded cheese, whether shredded or sliced, can be automaticallyportioned and placed in a food package in order to minimize handling andreduce packaging time and costs. Methods and apparatus for portioningand placing the extruded cheese in a food packaging include advancingthe generally homogenous cheese mass into a portioning chamber, followedby blocking an exit of the portioning chamber. Once the exit is blocked,a metering chamber can be filled with some of the generally homogenouscheese mass. Once the metering chamber is filled, the entrance of theportioning chamber can be blocked. Next, the exit of the portioningchamber can be unblocked and the metering chamber emptied to extrudesome of the cheese mass through openings. Once extruded through theopenings, the extruded cheese can be cut and dropped into a packagebeing advanced on a conveyor. Another package can be advanced to aposition for receiving the next extruded cheese mass, and the processrepeated. One or more portioning chambers and associated equipment canbe connected to a common pump, so that multiple conveyor lines ofpackages can be filled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a method for converting cheese pieces intocheese shreds according to an embodiment of the present invention.

FIG. 2 is an elevational side elevation view of portion of a cheeseshredding system including a vacuum-assisted loading extruder inaccordance with an embodiment of the invention.

FIG. 3 is an elevational side elevational view of a shred depositingportion of the cheese shredding system of FIG. 2.

FIG. 4 is a perspective schematic view of a die and cutter assembly,including a die plate having elongated orifices, forming part of theshred depositing portion of FIG. 3.

FIG. 5 is a partial cross-sectional view of the die plate of FIG. 4.

FIG. 6 is a partial front elevational view of the die plate of FIG. 4.

FIG. 7 is an enlarged plan view of a single representative die plateorifice of the die plate of FIG. 4.

FIG. 8 is an isolated plan view of an alternative die plateconfiguration which may be used to form part of the die and cutterassembly of FIG. 4.

FIG. 9 is an elevational side elevational view of a shred cutter whichcan be used with the shred depositing portion of the cheese shreddingsystem of FIG. 2.

FIG. 10 is a flow chart of a process for converting a cheese pieces intocheese shreds according to alternate embodiments of the presentinvention.

FIG. 11 is an elevational side elevation view of portion of a cheeseshredding system including a vacuum-assisted loading extruder inaccordance with the embodiment of FIG. 10.

FIG. 12 is an elevational side elevational view of a shred depositingportion of the cheese shredding system of FIG. 11.

FIG. 13 is a side cross-sectional view at the pump discharge showing thefunnel and the die plate attached.

FIG. 14 is a front perspective view of the discharge side of the dieplate at a piping or funnel outlet.

FIG. 15A is an exploded, side cross-sectional view of an alternative dieplate/funnel assembly, including a die plate, a harp plate with wires,and a wiper plate.

FIG. 15B is a front plan view of the alternative die plate of FIG. 15A.

FIG. 15C is a front plan view of the harp plate of FIG. 15A.

FIG. 15D is a front plan view of the wiper plate of FIG. 15A.

FIGS. 16A-D are microscopic representations of processed cheese andextruded cheese, at either 50 microns or 20 microns magnification.

FIG. 17 is a flow chart of a method for converting cheese pieces intocheese slices according to an embodiment of the present invention.

FIG. 18A is a schematic diagram of a portioning chamber in the purgingstage.

FIG. 18B is a schematic diagram of a portioning chamber in theportioning apparatus filling stage.

FIG. 18C is a schematic diagram of a portioning chamber in the filledstage.

FIG. 18D is a schematic diagram of a portioning chamber in the dischargestage.

FIG. 18E is a schematic diagram of a portioning chamber in the cuttingstage.

FIG. 19 is a perspective view of a portioning chamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a method and a system for producingcheese shreds or slices from cheese extrudates and portioning andpositioning the cheese pieces. More specifically, this invention relatesto extruding high moisture content mozzarella cheese at a temperatureless than about 50° F. through a unique die comprising a die platecontaining a plurality of orifices having elongated shapes, such asalmond or oval shapes, etc., and the resulting cheese extrudate strandsare intermittently cut along their lengths to provide individual cheeseshreds. This invention also relates to extruding a processed or naturalcheese at a temperature less than about 50° F. through a unique diecomprising a die plate containing a plurality of orifices havingelongated shapes, such as slots, and the resulting cheese extrudatesheets are intermittently cut along their lengths to provide discretecheese slices.

FIG. 1 is a flow chart of a method 10 for converting cheese pieces intocheese shreds according to an embodiment of the present invention. Inthis illustration, a large cheese barrel or block is subdivided intosmaller blocks and then cubes, which are fed into an extruder operableto work the cheese pieces into a homogenous mass in ambient or chilled(unheated) conditions and the convey the cheese mass to a multi-lanepressure depositor operable to split the primary cheese mass stream intosubstreams of given proportion which are fed to a respective die andcutter set-up operable to form cheese shred at a product temperaturebelow about 50° F.

Referring to FIG. 2, a system 100 is shown for forming cheese shreds,which includes a cheese mass forming and pumping assembly 200, and a dieplate assembly 300 (illustrated in more detail in FIG. 3). Theconversion of the cheese pieces to shreds begins in system 200. In thisnon-limiting example, a large barrel or block of cheese (e.g. about 640lb.) is initially cut into about 20-40 lb. blocks, which in turn areconverted into cubes (or alternatively, loaves, bricks, etc, shreds,etc.) at cubber 201. The cubes are introduced into a hopper 202 of ascrew extruder 203 equipped with a vacuum pump (not shown). The screwextruder works the cheese into cheese mass under ambient or chilled(unheated) conditions of less than about 50° F., and the resultinghomogenous cheese mass is discharged from the extruder and conveyedunder pressure to a water wheel 204, which subdivides the cheese massflow into cheese mass substreams. These cheese mass substreams arepumped to respective die assemblies 300 for discharge as extrudatestrands, which are intermittently cut to form discrete length shreds.

The cheese pieces used as feed material to system 100 may be naturalcheese (e.g., mozzarella, sharp cheddar, medium cheddar, mild cheddar,Swiss, etc.), process cheese (e.g., American cheese), soy cheese,imitation cheese, or combinations thereof. In one embodiment, the cheesepieces are natural cheese. In one embodiment, the cheese pieces aremozzarella cheese, particularly high moisture content mozzarella cheese.In a particular embodiment, the mozzarella cheese feed and shreddedproduct obtained therefrom with the inventive system have a fat content(on dry basis) of less than about 30 percent, moisture of about 52 toabout 60 percent, salt of about 1.6 to about 1.8 percent, and a pH ofabout 5.1 to about 5.3. The loose cheese pieces may be used in anygeometric shape as long as the largest dimension of the shape iscompatible with the feeding capacities of the hopper and the extruder.For example, in one embodiment, natural cheddar cheese may be precutfrom a large block or other source into cubes or other smaller regularshapes weighing about 4.5 kg (10 pounds) or less. For example, cubeshaving a size of about 5.1 cm to about 10.2 cm (about 2 to about 4inches) may be used for introduction into an extruder system fed by afrustoconical shaped hopper having about a 10.2 cm (4 inch) diameterbottom opening (e.g., circular, square, etc.) and an intermeshing twinscrew feed comprised of a pair of about 3.8 cm to about 5.1 cm (about1.5 to about 2 inch) diameter intermeshed screws. Other cheese pieceshapes also may be used alone or in combination with other geometries,such as cylinders, bars, shreds, slices (e.g., rectangular) and soforth.

The loose pieces of natural cheese or other dairy products are fed intoextruder hopper by any suitable means. The loose cheese pieces can bemechanically or manually fed into the hopper at a controlled rate. Forinstance, a conveyor may be used to transfer the loose pieces to thehopper from an intake bin (not shown). After entering the hopper, thecheese pieces descend into an extruder unit including a low-shear screwfeed. The low-shear screw feed particularly comprises an intermeshingtwin screw feed operable at low speeds and fitted with minimal clearancerelative to the inner surface of a generally cylindrical extruderchamber (barrel) that houses the twin screw mechanism. The screws eitherrotate in the same direction (co-current) or in opposite direction(counter-current) to each other. After entering the low-shear screwfeed, the cheese pieces are mixed and folded together. The extruder isequipped with a vacuum pump which evacuates air from space within theextruder barrel where the screw feed is housed and the cheese masstherein. In one particular embodiment, the vacuum pump is combined witha screw extruder as an integral unit. Commercially available vacuumpumps include, for example, VEMAG robot model HP-15C, manufactured byRobert Reiser & Co., which are packaged as integrated units with a twinscrew feed assembly for meat stuffing operations.

Another example of a suitable pump is the KS Vacuum Filler, Type P9 SE,manufactured by Karl Schnell GmbH & Co. KG, which is a gear-type vacuumpump and is presently preferred for use in producing cheese slices. TheSchnell gear pump uses a separate infeed auger drive which helps forcethe cheese into the pump gears, thus pushing the cheese through thepump. The Schnell gear pump can reduce the amount of shear upon thecheese as compared to the VEMAG. The Schnell gear pumps are capable of acontinuous feed, as opposed to the use of piston pumps which may alsoprovide low shear, but are non-continuous. Also, the Schnell P9 SE pumphas very low visual fat disruption, due to its low shear effect.

As the twin screw feed is working and conveying cheese mass forwardtowards the discharge outlet it keeps the product from being sucked intothe vacuum pump area. The vacuum-assisted loading of the extruderde-aerates the cheese pieces introduced into the screw feed and theresulting mass, such that a substantially continuous homogeneous masscan be formed which is substantially free of air pockets. Air pockets inthe cheese mass are undesirable as they tend to burst upon exiting theextruder after being under compression within the die, formingnoticeable structural defects in the extrudate. The removal of entrainedair from the cheese mass also helps provide a hard, dense extrudate. Thevacuum formed in the interior space of the screw housing by vacuum pumpalso helps draw cheese pieces from the hopper into the screw feed.

The cheese mass is conveyed as a viscous, substantially continuous,uninterrupted homogeneous mass by the twin screw feed out a dischargeoutlet 2020 of the extruder into piping 205 through which the cheesemass flows to water wheel 204 and before further processing includingshred production. During passage of the extrudable cheese mixturethrough the extruder barrel, the twin screw conveyor feed mechanism actson the cheese mass to convey it towards the discharge outlet in the formof two adjoining ropes of cheese material, which are compacted into asingle continuous mass in piping 205 after discharge from outlet 2020.The pitch of the intermeshing flighting is relatively close but withoutcausing contact between the two intermeshed screws. Also, clearancebetween the outermost peripheries and of the screws and the insidesurface of the extruder barrel is minimized to help reduce shear forcesthat may be exerted on the cheese mass as it is conveyed by the twinscrew assembly. For instance, while being driven in rotation atrelatively low speed, e.g., approximately 40 to approximately 60 rpm,the intermeshing twin screw arrangement can still aggregate, mix andcompact sufficient viscous cheese mass within the die to supportcontinuous extrusion of the cheese mass, while reducing shear forcesexerted on the cheese mass as it is conveyed to the discharge outletunder pressure. The extruder, including the vacuum pump, and integrallyattached hopper may be positioned as a unitary unit on an upraisedsurface, such as a mobile cart, or alternatively positioned on astationary surface such as a work floor, platform, countertop, etc.

As indicated, the cheese mass that exits the discharge outlet of theextruder is received in and pumped through piping or conduit 205 to awater wheel 204. The water wheel 204 divides the cheese mass flowdischarged from the extruder via integral manifold means into aplurality of separate cheese mass substreams of approximately equal flowand pumps them to respective die assemblies 300 for shred production.The water wheel may be a commercially-available configuration, such asone manufactured by Robert Reiser & Co. The water wheel 204 operatesusing a series of vertical vane pumps in a cylindrical housing. The vanepumps are directly connected by metal shafts which ensure that each vanepump rotates at the same rate and delivers the same amount of materialto its associated die and cutter set-up.

Referring to FIG. 3, each die assembly 300 includes a die 301 comprisinga die plate 303 having elongated orifices 305 separated by land areas304, an extrudate cutter 307, and a double gated shredcollector/dispenser 309. The elongated orifices 305, i.e.,through-holes, provided in die plate 303 are elongated shapes adaptedfor receiving, shaping and discharging cheese mass as extrudate instrand form (e.g., see FIGS. 4-6). In this embodiment, die plate 303 ismounted flush in a die plate support member 3010. The opposite side ofthe die plate (not shown) may be fed a cheese substream from the waterwheel 204 in piping including a flared fitting (not shown) that adjusts(viz., increases) the diameter of the feed conduit to be as large as theorifice pattern in the die plate 303. The die plate 303 may include acentral shaft receiving opening 308 for reasons indicated below relativeto the embodiment shown in FIG. 9. As indicated in FIG. 3, each cheesemass substream is discharged through the elongated orifices in the dieplate assigned to that product depositing lane as cheese extrudatestrands, which are intermittently cut along their length with theintegral cutter or slicer 307 associated with the die to form discretecheese shreds having cross-sectional shapes substantially correspondingto shapes of the orifices provided in the die plate.

Referring still to FIG. 3, in this arrangement the extruder is runcontinuously at constant pressure while flow rate gate 1 of shredcollector/dispenser 309 is kept open and gate 2 kept closed, toaccumulate a quantity of shredded cheese product (stage A). As shown,the shred collector/dispenser 309 includes a shred collecting chamber311 having openable/closable gate 1 at its upper end and another, gate2, at its lower end. Collector/dispenser 309 includes an upper housingstructure 313 which confines and guides falling cut shreds into chamber311 below. Then, as a food tray arrives under gate 2 ofcollector/dispenser 309, such as via a production line conveyor ormanually, gate 1 is closed and gate 2 of the shred collector/dispenser309 is opened to deliver the collected shredded product into the tray(stage B). After depositing collected quantity of cheese shred, gate 2is closed and gate 1 is opened again to restart the deposition cycle asdescribed above. In one particular embodiment, these various operationsare put under automated control.

In a particular embodiment, the cheese mass may be allowed to undergo aslight temperature increase during processing of several degrees (e.g.,about 3° F. or less), but measures are taken to ensure that the cheesemass is kept at a chilled temperature through discharge from the dieplate as extrudate strands. Among other benefits, this helps to improveand assure microbiological stability in the cheese product. In order tomaintain the temperature of the cheese mass at a temperature below 50°F. during processing including in the extruder, water wheel, and atleast until discharged from the die plate as shreddable strands, thesystem 100 may be set up in a refrigerated work space or room maintainedat chilled temperature sufficient for that purpose. Alternatively or inaddition thereto, the extruder, conduit, water wheel, and/or die platemay be equipped with cooling means, e.g., cooling jackets. Also, aspreviously indicated, a screw conveyor may be used that is driven inrotation at relatively low speed, which reduces shear forces exerted onthe cheese mass as it is conveyed to the discharge outlet underpressure. The use of low shear conditions in the extruder hasadvantages. For example, occurrence of significant fat coalescence(e.g., fat globule formation), oiling (e.g., oil/solid mass phaseseparation), and/or protein aggregation is minimized, thereby improvingproduct texture, homogeneity, and firmness.

Although FIGS. 1-3 illustrate a four-lane pressure depositorarrangement, it will be appreciated that one or any multiple number oflanes can be incorporated into the method and system. For instance, inoptional scheme 101 shown in FIG. 1, only one die cutter set up issupported, so the four lane pressure depositor is not needed. In thisoptional mode, cheese mass is directly fed from the discharge outlet ofthe extruder to the die and cutter set up. It also will be appreciatedthat the shredding system could be operated without the gated collectorsat the depositing subsystem by intermittently extruding and cuttingextrudate strand in a manner timed to coincide with tray or food productplacement beneath the die plate.

Referring to FIG. 4, the die plate 303 may be synthetic polymer or metalconstruction. For instance, die plate 303 may be constructed ofstainless steel, aluminum, etc. It alternatively may be formed of moldedplastic construction. The plastic may comprise, e.g., ultra highmolecular weight polyurethane. The orifices 305 may be formed in the dieplate by machining techniques suitable for the metal or plasticconstruction, as applicable. Alternatively, a metal or plastic die platemay be cast, or a plastic die plate injection molded, as a unitarystructure including the orifices.

The orifices 305 may comprise passageways having a constantcross-sectional shape through the thickness of the die plate.Alternatively, as illustrated in FIG. 5, the orifices 305 may comprisetwo portions comprising a first passageway portion 501 at the input(i.e., cheese-mass receiving) side 3032 of the die plate 303 having afrustoconical shape that is angled at about 45° (i.e., angle a) relativeto the product flow direction, and which converges to and communicateswith a second passageway portion 502 at the extrudate discharge side3034 of the die plate 303 that includes discharge orifice 305 having ashape that corresponds to the desired cross-sectional shred shape. Thetapered first passageway 3032 effectively smoothens the surface of theresulting extrudate strands. FIG. 6 shows the entry openings 601 of thefirst passageways 501 at the rear side 3032 of the die plate in hatchedlines, which are hidden in this frontal view, and the shape of theorifices 305 in solid lines.

For a die plate of approximately 15.2-20.3 cm (approx. 6-8 inch)diameter and an approximately 9.5 mm (⅜ inch) thickness, the plate mayhave approximately 100-140 orifices with the elongated shapes, such asalmond-, oval-, elliptical-, or rectangular-shapes, and the like. Theorifices are space-apart from one another and separated by land portionsin the die plate. In one embodiment, the orifices have a majordiameter/minor diameter ratio of about 2.25:1 to about 1.75:1. Theorifices have a major dimension of about 6 mm to about 6.5 mm, and aminor dimension of about 3 mm to about 3.25 mm. In one embodiment, thedie plate may have a thickness, which corresponds with the length of thepassageways therein, approximately 6 mm (0.25 inch) to approximately 13mm (0.5 inch).

Referring to FIG. 7, in one non-limiting embodiment, the dimensions ofthe orifices provided in the die plate when used for extruding highmoisture (e.g., about 52%) cheeses at temperatures less than about 50°F. are about 3.175 mm (0.125 inch) in the minor axis “y” direction, andabout 6.35 mm (0.250 inch) in the major axis “x” direction. The radii ofcurvature R₁ and R₂ of the upper and lower arc segments, respectively,defining the almond shaped orifice is about 2.3 to about 2.7.

Referring to FIG. 8, an alternative die plate 3030 configuration isillustrated, wherein the orifices 305 are arranged in vertical columnsand diagonally-oriented rows in which orifices are staggered in locationto provide substantially even spacing between orifices in a given columnor row, and between orifices in adjoining columns and rows.

After being discharged from die plate 303, the extrudate cheese strandstypically are intermittently cut into discrete non-continuous shredswith any suitable means for that purpose. The cutting or slicing meansmay comprise a knife or other cutting device, such as a wire cutterknife, an air knife, a metal guillotine, rotary cutter, knock-off or aflicker wheel, and so forth. The motion of the cutting device and exitspeed of the formable food product are two factors that regulate thelength of the final shred product. The cutting device may include amechanism for cutting the continuously extruded strands to desiredlengths, depending on the food application. For example, the shredlengths formed may be about 1 to about 15 cm, although other lengthsalso can be provided. In some embodiments, the cutting device may have areciprocating or circular motion. For instance, as illustrated in FIG.4, a harp cutter 407 fitted with single cutting wire 409 is equipped toreciprocate vertically up and down, as indicated by the arrows, betweenits illustrated pre-cutting position 408 and extended position 410during a cutting stroke, to cut the cheese extrudate strands to desireddiscrete lengths.

Referring to FIG. 9, in another embodiment a cutting assembly 900includes a multiwire cutting member 901 and a pneumatic drive mechanism920 operable to controllable rotate the cutting member 901 reciprocallyback-and-forth in a counter-clockwise/clockwise circular motion relativeto the cheese strand being extruded from die plate 303 to intermittentlycut the cheese extrudate strands into discrete shreds. The multiwirecutting member 901 includes a cutting wire support frame 902 having acircular rim portion 903 and a flanged portion 909, and support arms 904extend between the rim portion and a central collar support member 905.In this illustration, three equidistantly spaced support arms 904 areprovided to connect the rim portion 903 to the central collar supportmember 905, although it will be appreciated that different numbers ofsupport arms may be used. A plurality of wires 906 are strung radiallybetween the central collar member 905 and the circular rim portion 903and are rigidly connected to those components at opposite ends of eachwire so that the wires are taut and can slice extrude efficiently.String-lock screws 907 or other suitable connecting means may be usedfor this purpose at the opposite ends of the wires. In thisillustration, twelve wires are strung between the rim portion 903 andcollar support member 905 in the open spaces 908 between eachneighboring pair of support arms 904. The central collar support member905 has a central hole 910 adapted to receive a threaded shaft 930 thatis mounted rigidly to the die head 931 that supports die plate 303,which also has a central opening 308 (see FIG. 4) through which thethreaded shaft 930 can be received. A biasing spring (not shown) isfitted onto the shaft 930 underneath collar 905. A shaft nut 912 isfitted onto threaded shaft 930 at the opposite outer side of collar 905.The position of the nut 912 on threaded shaft 930 is manually adjustableso that a slight gap can be provided between the wires 906 and the outerface lands 304 of the die plate 303.

Pneumatic drive mechanism 920 includes a pneumatic cylinder 921 housedin a sleeve 922 which is bolted (923) to a bracket arm 940 that isintegrally connected to the die head 931. The pneumatic cylinder 921 ishingably connected at one end (not shown) to clip member 924 that isfastened to a flanged portion 909 of rim portion 903 of cutting member901. Pneumatic cylinder 921 is also fitted with a valve stem 922 throughwhich needle valve control is made, such that pressurization causescylinder 921 to stroke or translate laterally towards cutter part 901,which in turn causes a counter-clockwise rotation of cutting member 901,as indicated by the direction arrows in FIG. 9. The cutting assembly 900is configured such that the cylinder stroke moves each cutter wire 906across about 2-4 columns of orifices 305 effective to cut extrudatestrands without smearing the extrudate. On relieving air pressure to thecylinder 921, the cylinder 921 retracts in the opposite lateraldirection back to its original at-rest position, which causes clockwiserotation of cutting member 901 effective that the wires 906 can againcut extrudate strands while moving in the opposite rotational direction.In a particular embodiment, the movement of the cylinder 921 is timedwith the discharge rate of the cheese extrudate so that shreds can beformed of desired discrete lengths. In another alternative cuttingconfiguration, a rotating multi-bladed prop-type slicer may be mountedon the outer face of the die plate and rotated at a speed timed to cutextrudate strands at desired lengths.

Referring to FIGS. 10-12, alternative shredding systems of embodimentsof this invention are illustrated. In mode 702, this arrangement issimilar to the system described in FIGS. 1-3 except that a three-waydiverter valve is interposed between the water wheel and die and cutterset-up to allow diversion of cheese mass from a cheese mass substreamback into the extruder when no tray or food product is ready to receiveshredded product.

Referring to FIGS. 13-17, alternative embodiments for a cheese slicersystem 30 are illustrated. This system may similarly feed cheese piecesinto an extruder hopper where the cheese pieces can also descend into anextruder unit including a low-shear vacuum pump that works the cheeseinto a cheese mass. The cheese pieces pass through a low-shear pump,preferably a gear pump such as the KS Vacuum Filler, Type P9 SE,manufactured by Karl Schnell GmbH & Co. KG, which feeds the cheesethrough it to the discharge outlet 22. At the discharge outlet 22 of thepump chamber the cheese mass may be forced through a length of outletpiping followed by a funnel 16 at its discharge end. At the funneloutlet 16 b the cheese may be extruded through a die plate 18 with wiresattached, or another similar cutting device attached. The material ofconstruction of the funnel may be either metal or plastic, andpreferably may be stainless steel metal. Furthermore, a water wheel andflow dividers are not necessary with the slicer system.

Referring to FIG. 13, a portion of a cheese slicer system 30 is shown atthe discharge outlet 22 from the pump chamber. As the cheese mass isforced out of the pump chamber it may pass through a length of pipe (notshown) at the discharge outlet 22 of the pump chamber. Preferably, thepump outlet 22 and the outlet piping may both have diameters of about3.8 cm to about 9.0 cm (about 1.5 inches to about 3.5 inches),preferably about 6.4 cm in diameter (about 2.5 inches), although theoutlet 22 of the pump chamber may also be a different diameter than theoutlet piping and may vary from about 3.8 cm to about 13.0 cm (about 1.5inches to about 5 inches). The length of the outlet piping may vary, andpreferably may be as short as possible. Optionally, a size reducer 20,such as a pipe reducer or an additional funnel, may be used at thedischarge outlet 22 of the pump chamber and just prior to the inlet ofthe outlet piping. To minimize the shear effect upon the cheese mass asit exits the pump, the discharge outlet 22 of the pump should be aboutthe same diameter as the outlet piping; when that is not the case, thena reducer 20 may be used to make them the same. The inlet of the reducer20 can be sized to fit the discharge outlet 22 of the pump chamber, andmay have a major diameter between about 3.8 cm to about 13.0 cm. Theoutlet of the reducer 20 may be sized to fit the diameter of the outletpiping, and may have a minor diameter of about 3.8 cm to about 9.0 cm,and preferably about 6.4 cm.

At the discharge end of the outlet piping (not shown) a funnel 16 may beattached, which can also be downstream of a reducer 20, if one is used,or alternatively may be attached directly to the pump outlet 22. Thefunnel 16 can be used to shape the cheese mass to a required shape forforming slices upon exiting and to compact the cheese firmer, and mayalso further reduce the size of the cheese mass stream that exits it.Any shape cheese mass may be made coming out of the funnel 16 with theoutlet 16 b shaped accordingly, and typically a generally rectangularshape is desired upon exiting the funnel 16. The inlet 16 a of thefunnel 16 may be sized to fit the diameter of the outlet piping. Forexample, the diameter of the inlet 16 a to the funnel 16 and the pipediameter may both be from about 3.8 cm to about 9.0 cm (about 1.5 inchesto about 3.5 inches), preferably about 6.4 cm in diameter (about 2.5inches). The outlet 16 b of the funnel 16 may be generally rectangularor another non-circular shape, such as a star shape, an oval shape or asquare shape, for example. If a generally rectangular shape is used, theoutlet 16 b of the funnel 16 may be sized at about 1.2 cm to about 3.8cm (about 0.5 inches to about 1.5 inches) on a minor side and about 1.5cm to about 6.6 cm (about 0.6 inches to about 2.6 inches) on a majorside, and preferably may be about 2.5 cm on a minor side and about 4.0cm on a major side (about 1.0 inch on a minor side and about 1.6 incheson a major side). The cross-sectional area of the inlet 16 a of thefunnel 16 may be greater than the cross-sectional area of the outlet 16b.

The funnel 16 and possibly a reducer 20 may be necessary to helpminimize the shear on the cheese as the cheese transitions to a smallerdiameter pipe from a larger diameter. When the funnel is used alone orwith a reducer, it gradually tapers the size from a large diameter to asmaller diameter, thus minimizing the shear upon the cheese. High shearmay occur when an outlet is reduced in diameter abruptly and is notdesirable because it may make the cheese softer, which can cause thetexture and the taste of the cheese to change undesirably.

At the outlet 16 b of the funnel 16 a die plate 18 may be attachedaligned with the discharge outlet of the funnel 16 or a pipe that isdownstream of the pump. The die plate 18 may comprise one or a pluralityof harp wires 24, as illustrated in FIG. 14, or other similar cuttingelements, strung across the discharge side 18 b of the die plate 18 fromone end of the die plate to the other. The wires 24 can be strungparallel to one another in a direction transverse to a machine directionand the wires 24 may be located at or near the outlet 16 b of the funnel16. The die plate 18 may contain a plurality of elongated orifices atthe die plate 18 that may be generally rectangular in shape andsubstantially parallel to each other, transverse to a machine direction.The elongated orifices may be defined by the edges of one or more wires24, for example, which may straddle the inlet 18 a and discharge sides18 b of the die plate 18 and in the case of the outer edge slots, forexample, the orifice may be defined by the die plate wall, where theorifices may be spaced apart from one another and separated by the wires24. Typically 5 or 7 wires may be used, which yield about 6 or about 8slices, respectively. The wires 24 may be of a thickness between about0.8 mm to about 1.3 mm (about 16 to 20 gauge), more preferably at about1.0 mm, which corresponds to approximately an 18 gauge wire. In general,the smaller the wire size the better the cut. However, if the wire istoo small (i.e., very fine) it may break. The inlet side 18 a of the dieplate 18 may be sized to fit the outlet 16 b of the funnel 16 and ispreferably also a generally rectangular shape. The die plate 18 may havea minor dimension from about 1.2 cm to about 3.8 cm (about 0.5 inches toabout 1.5 inches) and a major dimension from about 1.5 cm to about 6.6cm (about 0.6 inches to about 2.6 inches), which is sized similarly asthe outlet 16 b of the funnel 16, and preferably may be about 2.5 cm byabout 4.0 cm (about 1.0 inch by about 1.6 inches). The material ofconstruction of the die plate 18 may be either metal or plastic, andpreferably may be stainless steel metal.

FIGS. 15A-D depict an alternative type of die plate assembly from FIG.14. In FIG. 15A, the alternative die plate 118 is similar to the dieplate 18 in FIG. 14 except that it does not contain harp wires strungacross the die plate 118. Rather, the alternative die plate 118 has anopening 118A such that the cheese exiting the funnel may pass throughthe opening 118A, before passing through the harp plate 218.Additionally, the alternative die plate 118 may also have small grooves224, as seen in FIG. 15B, along two opposing sides for receiving harpwires attached to a harp plate that may extend over the die plate whenthe harp plate 218 is placed adjacent to it. The die plate 118 maycomprise one or a plurality of grooves 224 on each of the two sides, andpreferably the number of grooves per side is equal to the number of harpwires 24 strung across the harp plate 218. The grooves 224 on the dieplate 118 may receive the harp wires 24 therein when the harp plate 218is placed adjacent to it, and allows for a tighter and more flush fitbetween the die plate 118 and harp plate 218, to be discussed in moredetail below. The inlet of the die plate 118 may also be sized to fitthe outlet of the funnel 16 and preferably may be generally rectangularshaped as in the die plate 18 in FIG. 14.

The harp plate 218 may be attached adjacent to the discharge side of thedie plate 118, which is shown detailed in FIG. 15C. The harp plate 218may be the same size as the die plate 118 or it may be larger and theharp plate has an opening 218A that may be the same size as the dieplate opening 118A or larger. Preferably the opening 218A of the harpplate 218 will be the same dimension as the opening 118A in the dieplate 118. The harp wires 24 may be strung across and attached at thedischarge side of the harp plate 218 across the opening 218A andparallel to one another in a direction transverse to a machinedirection, similar to the positioning of the harp wires 24 on die plate18, as discussed previously. The harp wires 24 on the harp plate 218function similarly to the harp wires 24 on the die plate 18 in FIG. 14,and help define the elongated orifices which receive the cheese massexiting the funnel and the die plate and provide the cheese extrudatesheets.

Optionally, a wiper plate 318, as shown in greater detail in FIG. 15D,may also be used and placed adjacent to the discharge side of the harpplate 218. The wiper plate 318 has an opening 318A which functions toallow the cut cheese extrudate sheets to pass through it and to smoothout and shape the newly cut cheese slices by wiping off or removing anyresidual pieces or loose cheese from the newly cut cheese slices as theypass through the opening 318A and brush against the outer edges of theopening 318A.

An alternative to the gear pump may be a piston-type pump, such as theOPTI-220, manufactured by Marlen Research Corporation. A piston pump,however, cannot continuously feed the cheese mass, as the gear pump can.The piston pump can push the cheese through using a piston and as itschamber fills up with the cheese it applies a force against the cheeseto advance it in a forward machine direction. Some piston pump modelsmay also include a reducer, such as an additional funnel, already builtinto the pump itself and located at the pump outlet. This additionalfunnel may already reduce the size of the outlet down to the diameter ofthe outlet piping. At the discharge end of the outlet piping the funnelwith the attached die plate may be positioned. The parameters for thefunnel and die plate in this example can be similar to those discussedabove.

An example of the overall slicing process is illustrated in FIG. 17,which is a flow chart of a method 101 for converting cheese pieces intocheese slices. In this process, a large cheese barrel or block issubdivided into smaller blocks and then cubes, which are fed into anextruder operable to work the cheese pieces into a homogenous mass inambient or chilled (unheated) conditions and then convey the cheese massto the discharge outlet by the force from the extruder/pump. The cheesemass may advance in a forward machine direction (i.e., longitudinally)through the discharge outlet and into an outlet piping. If the diameterof the pump chamber outlet is approximately 7.6 cm then no reducer isneeded and the diameter of the outlet piping may also be approximately7.6 cm. After the cheese mass passes through the outlet piping it canenter into the inlet 16 a of the funnel 16, which may further reduce thecheese mass to a smaller sized diameter as well as shape the cheese massto an alternate shape upon exiting the funnel 16. As the cheese massexits the funnel 16 it can be extruded through a plurality of elongatedorifices at a discharge side 18 b of the die plate 18, which may beattached at or near the outlet 16 b. The die plate 18 may contain anumber of wires 24, which cut the cheese mass as it passes between theplurality of elongated orifices and cuts the cheese mass into extrudatesheets stacked on top of one another, and preferably into six to eightsheets. As the cheese extrudate sheets exit the die plate 18, the sheetsmay be cut by an optional slicer at the discharge side 18 b of the dieplate 18 or by a separate cutting mechanism further downstream from thedie plate 18. The cheese sheets may have the following dimensions of aheight between about 1.2 cm to about 3.8 cm (about 0.5 inches to about1.5 inches) and a width between about 1.8 cm to about 4.3 cm (about 0.7inches to about 1.7 inches), and preferably a height of about 2.5 cm anda width of about 3 cm (about 1.0 inch high and about 1.2 inches wide).

When a separate cutting mechanism is used, the sheets may be extrudeddirectly onto a conveyor which transports the sheets to a cutting deviceor slicer after exiting the die plate. The conveyor may be equipped witha knife, such as an ultrasonic knife, which cuts the sheets into slicesof desired length. These final slices may be sized such that a stack ofsix slices, for example, would be about 2.5 cm tall, about 4.0 cm longand about 3.0 cm wide (about 1.0 inch by 1.6 inches by 1.2 inches),where the length is parallel to a machine direction and the height andwidth are transverse to the machine direction. The motion of the cuttingdevice and exit speed of the sheets are two factors that regulate thelength of the final sliced product. For example, the cheese extrudatesheets may exit the funnel and die assembly as long strips or ribbons ofcheese and pass in a machine direction through the cutting assemblyhaving a knife which cuts the cheese extrudate sheets transverse to themachine direction, and where the knife blade may travel longitudinally,for example. The cheese slices may all be of substantially equal lengthsince the rate of cutting the sheets should remain relatively constant.After the cheese sheets are cut into slices, the slices may continue totravel in a machine direction further down a conveyor where the slicescan be picked off the line and packaged in a food container or tray.

It will be appreciated that this invention is especially useful fordirectly converting chilled high-moisture cheeses, such as refrigeratedmozzarella cheese having a moisture content of at least about 52%, intoshredded form without needing to provide heated conditions in theinventive shredding system. In a particular embodiment, the cheesepieces are introduced into, processed within the extruder, and extrudedin strand-form at the die plate, at a temperature less than about 45°F., more particularly, less than about 40° F. In one aspect,refrigerated cheese is fed into the extruder chamber, and the cheesemass formed therefrom in the extruder is conveyed to the die plate,while being maintained under refrigerated temperature conditions. In oneaspect, the temperature of the cheese when extruded at the die plate isabout 32° F. to about 45° F., particularly about 35° F. to about 45° F.In this manner, it is possible to directly convert refrigerated orotherwise chilled cheese pieces into shreds of approximately uniformdimensions without the need to heat the cheese to flowable or moltenstate to assist extrusion, which further avoids the need to providepost-extrusion quench procedures to stabilize and avoid shape distortionfrom occurring in otherwise hot extruded shapes. This inventive methodand system avoids the need for process control over complex systemsincorporating heating jackets or internal heating systems in theextruder, piping, pumps, dies, etc. This reduces process complexity,requirements and costs.

It will further be appreciated that this invention is especially usefulfor converting an extruded cheese mass into a sliced form withoutneeding to provide heated conditions in a similar fashion as with theshredding system.

Also, although use of ingredients in addition to the cheese pieces arenot categorically excluded from the method, no processing aids orproduct modifiers, e.g., water, salt, plasticizers, emulsifiers, etc.,need be included with the cheese pieces fed into the process systemdescribed herein to provide high quality cheese shred product. Forinstance, raw natural or process cheese material by itself can beprocessed in the shredding system without the need for co-ingredients.Additional edible ingredients, such as meat pieces, vegetable pieces,herbs, spices, vitamins, calcium or other minerals may be optionallyadded to the cheese mass via the hopper to the extent they aredispersible in the cheese mass and do not obstruct or blind the orificeson the die plate.

The Examples that follow are intended to illustrate, and not limit, theinvention. All percentages described herein are by weight, unlessindicated otherwise.

EXAMPLE 1

Leprino brand mozzarella cheese (53% moisture) with starch was cut into15.2 cm (6 inch) ×7.6 cm (3 inch) pieces weighing approximately 0.5lbs.The cheese temperature at the time of use was about 35° F. and was stillabout 35° F. after extrusion.

A customized die plate was fitted to an extrusion system, as describedbelow. The die plate was molded rigid plastic construction having an 18cm (7 inch) diameter and 0.95 cm (⅜inch) in thickness. The plate had 117orifices formed in it having almond-shapes, similar to that illustratedin FIG. 6, which were arranged in the die plate in the patternillustrated in FIG. 4. The orifices extended through the entirethickness of the plate between its opposite exposed faces. Thedimensions of the shred orifices were approximately 6.35 mm (0.250 inch)as the major diameter dimension extending laterally across the orificeby approximately 3.175 mm (0.125 inch) as the minor diameter dimensionextending vertically across the orifice. The orifices were separated bylands in the die plate. The orifices had cross-sectional shapescorresponding to the desired cross-sectional shape of the cheesestrands. The cheese temperature at the time of use was about 35° F. andwas still about 35° F. after extrusion.

A VEMAG ROBOT model HP-15C vacuum pump/extruder, manufactured by RobertReiser & Co. was set-up to operate with the following settings:Weight=0068 000, Pause=0050, Twist=1500, Speed=0, PI=0. The pressure inthe system was between about 300 and about 350 psi. Approximately 80pounds of the cheese pieces were dumped into the extruder hopper. Thescrews were operated at about 75 rpm to mix, knead, and compact thecheese pieces into a homogenous cheese mass before exiting the dischargeoutlet of the extruder. The throughput rate was about 8 lb/min. Thecheese mass exiting the vacuum pump/extruder unit was conducted to aReiser 6-inch water wheel, which divided the cheese mass into separateequal streams collected in respective vane pumps. The water wheelsupported die plates mounted on two separate deposition lanes. Thedivided cheese streams were each pumped from the water wheel to a dieplate, described above, and extruded as continuous strands, i.e., thecheese extrudate. The extrudate product was extruded at 35° F. using thedie. A wire cutter was used to cut the continuous strands into discretecheese shreds having lengths of about 3 cm to about 4 cm. The cheeseshreds had cross-sectional shapes along their lengths that substantiallycorresponded to the die plate orifice shapes.

EXAMPLE 2

A funnel 16 at the discharge of an outlet piping was used together witha reducer 20 at a pump outlet 22 to gradually transition between pipesizes when making extruded cheese and was found to help maintain thecheese structure so that it closely resembled a processed, non-extrudedcheese structure. This is illustrated in FIGS. 16A-D, which showmicroscopy results comparing the internal structures of processed cheesethat had not been extruded versus extruded cheese using thefunnel-reducer system. FIGS. 16A and B depict the control cheese, orprocessed, non-extruded cheese. FIG. 16A was magnified at a scale of 50microns, and FIG. 16B was magnified at a scale of 20 microns. The cheesesamples were tested using a nile blue staining technique which stainedthe fat particles in the cheese so that they were more visible whenperforming the microscopy testing. The fat particles in the non-extrudedcheese appeared as droplets or round spheres with two sizes of fatpopulations of either about 2 um or about 5-10 um in diameter, which istypically common in processed, non-extruded cheese.

FIGS. 16C-D depict the same degree of magnification for cheese for theextruded cheese samples. The cheese mass passed through a VEMAG ROBOTmodel HP-15C vacuum pump/extruder, manufactured by Robert Reiser & Co.and having a pump outlet of about 10.2 cm. A pipe reducer was placed atthe pump outlet to reduce the diameter from about 10.2 cm to about 7.6cm. An outlet pipe with a diameter of about 7.6 cm was located at thepump outlet and after the reducer. A funnel was located at the end ofthe outlet piping and had an inlet of about 7.6 cm and a generallyrectangular outlet of about 3.0 cm by about 4.0 cm. In both FIGS. 16Cand D, the regular shaped fat droplets were visible, as in the controlsamples, however a very small number of coalescent fat droplets werealso present, which were depicted as slightly irregular shaped spheres.Although, the protein matrix of the extruded cheese was slightly looserthan the control and there was a minor degree of coalescent fat present,overall there was no significant difference between the two samples.

Referring to FIGS. 18A-19, a portioning chamber 40 is illustrated. Theportioning chamber 40 generally provides a method of dispensing apredetermined amount of cheese from the system and positioning thatamount of cheese in a food package. Incorporating a portioning chamber40 into the cheese forming process allows the cheese to intermittentlyexit from the die assembly in the predetermined portions. Thisintermittent discharge is useful for filling food packages located on aconveyor. For example, if the Lunchables® packages are arranged on aconveyor located underneath the die assembly, the portioning chamber 40can direct the cheese into a particular compartment of the package andfurther meter the cheese exiting comprises a die plate 305 with holes ora die plate 18 with harping wires, a portioning chamber 40 can beemployed before the die plate such that a predetermined portion ofcheese will exit the die plate and be positioned into the foodpackaging.

The portioning chamber 40 as shown in schematic form in FIGS. 18A-Ecomprises an inlet valve 42, a exit or outlet valve 44, and a meteringchamber 46. The portioning chamber 40 is connected upstream to a pumpand downstream to a die assembly, such as the types disclosed herein.Portioning of the cheese that exits from the die assembly 18 or 300occurs in several stages. Referring to FIG. 18A, a portioning chamber 40is shown in schematic form. FIG. 18A depicts the portioning chamber 40in a start-up, purging stage. The purging stage can be used to fill theportioning chamber 40 and prepare the system for operation, and thus mayonly be necessary prior to beginning of the packaging process. Duringthe purging stage, the cheese flows or advances freely into and out ofthe portioning chamber 40 and is thus moved through the die plate 18,300. The inlet valve 42 is shown in the open position in FIG. 18A. Theinlet valve receives cheese mass from the pump and is located upstreamfrom the die plate. The outlet valve or exit 44 of the portioningchamber 40 is in the open position. The metering chamber 46 is shown inthe freely movable position. In this position, the fill position ofmetering chamber 46 is affected by the speed at which cheese mass isentering and exiting the portioning chamber 40. The die 48 is attachedto the portioning chamber 40 adjacent and downstream from the outletvalve 44. In another embodiment, the outlet valve 44 is locateddownstream of the die 48. A cutoff element 50 is located at thedischarge of the die 48 in FIG. 18A. During the purging stage, cutoffelement 50 is in the extended position allowing the cheese to dischargefrom the die 48 in a relatively continuous stream.

FIG. 18B depicts the portioning chamber 40 in the fill stage. At thebeginning of the fill stage, the outlet valve 44 closes and the cheesemass beginnings filling the portioning chamber 40. While the portioningchamber is filling with cheese mass, the metering chamber 46 fills aswell and then when the metering chamber 46 is filled to a predeterminedlevel, the inlet valve 42 closes as shown in FIG. 18C. The inlet valve42 is preferably pressure sensitive and can close when the portioningchamber is filled to a predetermined level. At this time, the pump thatadvances the cheese mass into the portioning chamber 40 temporarilyshuts off. As discussed below, a production line may have four or eightsubstreams of cheese exiting an assembly and deposited into differentstreams of packages being continuously or intermittently advanced onconveyors or the like. The pump in the assembly preferably keepsadvancing cheese until all four or eights of the inlet valves 42 of theportioning chambers 40 have shut. Before the four or eight portioningchambers 40 of a line enter the discharge stage, all of the inlet valves42 must be shut.

FIG. 18D shows the portioning chamber 40 in the discharging stage.During the discharge stage, the metering chamber 46, which includes apump or valve, discharges a portion of the cheese mass in the portioningchamber 40 through the die 48. In one preferred embodiment, the meteringchamber 46 advances 1.2 ounces of cheese from the portioning chamber 40and through the die 48. The cheese as it is pushed out of the die isdirected toward food packing 52, such as a tray. Then, as shown in FIG.18E, the cutting element 50 is activated to separate the cheese piecefrom the cheese mass inside the portioning chamber 40. After the cheesehas exited the system, the process repeats itself.

The portioning chamber 40 preferably, though not necessarily, has abend, elbow, y-connection, or other redirecting capability to guide thecheese toward the food packages 52 located on a conveyor. A plurality ofportioning chambers 40 can be attached to a pump making the homogenouscheese mass. In one embodiment, a manifold downstream of the pumpdirects cheese mass into four cheese substreams of generally equal flowand then advances the cheese to four portioning chambers 40 beforemoving the cheese to the die assemblies 18, 300. In another embodiment,a manifold directs cheese mass into eight substreams of generally equalflow and then pumps the cheese to eight portioning chambers 40 andsubsequently to eight die assemblies 18, 300. A conventional speedproduction line completes 30 cycles per minute. Thus, the process offilling and discharging the metering chamber 46 occurs 30 times in oneminute. For a conventional speed producing line having four trays orfood packages 52 across, the line fills 120 trays per minute. The dwelltime for such a conventional line is 1.33 seconds. On a high speedproduction line 200 trays are filled per minute. A high speed linepreferably has a 4 by 2 tray configuration and completes 25 cycles perminute. The dwell time for such a high speed line is 1.6 seconds. If atray is not located below the die assembly 18, 300, the cheese will notdispense. This can occur via a sensor that indicates to the portioningchamber 40 whether or not to advance cheese mass or the substream canhave a manual shut off.

Referring to FIG. 19, the portioning chamber 40 is shown connected tothe pump. Thus, instead of having the discharge outlet 2020 or 22 feedthe cheese mass directly to the die assembly 18, 300, the dischargeoutlets will feed into the portioning chamber 40. Although some of thecomponents in FIG. 19 have been illustrated as manual components, higherline speeds can be achieved by using electrically or otherwise automatedactuation. Downstream from the inlet valve 42, the portioning chamber 40includes a metering chamber 46. The outlet valve 44 is shown adjacentthe die plate 48 in this example. However, as discussed above, otherconfigurations are contemplated. For example, the outlet valve 44 may beseparated from the die assembly. While the configuration in FIG. 19shows a tee connection directing the cheese mass toward the die plate 48and the metering chamber 46, in another preferable embodiment theconnection would be an elbow or y-connection to reduce back pressure inthe system. In another embodiment, the cutting element 50 would be awire cutter instead of a blade.

While the invention has been particularly described with specificreference to particular process and product embodiments, it will beappreciated that various alterations, modifications and adaptations maybe based on the present disclosure, and are intended to be within thespirit and scope of the present invention as defined by the followingclaims.

1. A method for forming bulk cheese into extruded portions of cheesecomprising: forming a generally homogenous cheese mass from a pluralityof cheese pieces; advancing at least some of the generally homogenouscheese mass into a portioning chamber, the portioning chamber having avolume, an entrance, an exit and a metering chamber disposed between theentrance and exit, the metering chamber having a volume smaller than thevolume of the portioning chamber; blocking the exit of the portioningchamber; filling the portioning chamber with some of the generallyhomogenous cheese mass, such that the metering chamber also fills withsome of the generally homogenous cheese mass; blocking the entrance ofthe portioning chamber; unblocking the exit of the portioning chamberafter filling the metering chamber with the generally homogenous cheesemass; and emptying the metering chamber to extrude some of the generallyhomogenous cheese mass through the exit of the portioning chamber andthrough a die plate downstream thereof, thereby forming an extrudedcheese portion.
 2. The method of claim 1, further comprising cutting theextruded cheese, the extruded cheese being cut by a cutting devicedownstream from the die plate to form the extruded portions of cheesehaving a desired length.
 3. The method of claim 2, further comprisingdepositing the extruded portions of cheese directly into a food package.4. The method of claim 2 wherein the die plate comprises a plurality ofdischarge orifices.
 5. The method of claim 2, wherein the die platecomprises one or a plurality of parallel extending cutting elementstransverse to a machine direction at a discharge side of the die plate.6. The method of claim 5, wherein the cutting elements are one or morewires.
 7. The method of claim 6, wherein the wires are attached to aharp plate that is attached to the die plate.
 8. The method of claim 6,wherein the generally homogenous cheese mass is cut into extrudedsections as it passes over the wires at the discharge side of the dieplate.
 9. The method of claim 6, wherein the wires have a thickness ofabout 0.8 mm to 1.3 mm.
 10. The method of claim 2, wherein the die platecomprises a plurality of elongated orifices.
 11. The method of claim 10,wherein the elongated orifices are comprised of at least one of:generally almond shaped; generally oval shaped; generally rectangularshaped.
 12. The method of claim 11, wherein the die plate has athickness in the longitudinal direction of about 6 to about 13 mm. 13.The method of claim 1, wherein the cheese mass is extruded at atemperature less than 50° F.
 14. The method of claim 1, wherein thegenerally homogenous cheese mass comprises at least one of sharp cheddarcheese, medium cheddar cheese, mild cheddar cheese, Swiss cheese,American cheese, Gouda cheese, soy cheese, mozzarella cheese, pastafilata cheese, and Edam cheese.
 15. The method of claim 1 furthercomprising blocking the entrance of the portioning chamber when apredetermined level of generally homogenous cheese mass is reached inthe metering chamber.
 16. The method of claim 1 further comprisingunblocking the exit of the portioning chamber when a predetermined levelof generally homogenous cheese mass is reached in the metering chamber.17. The method of claim 4 wherein the plurality of discharge orificescomprise a first passageway portion having a frustoconical shape angledat about 45° at an input side of the die plate.
 18. The method of claim1 further comprising working the plurality of cheese pieces into thegenerally homogenous cheese mass in an extruder.
 19. The method of claim1 wherein the portioning chamber is free from obstructions that willblock flow between its entrance and exit.